3.Application and evaluation of droplet digital polymerase chain reaction in detection of severe acute respiratory syndrome corona virus-2
CHEN Shuang ; WANG Ming-yue ; ZU Zhen ; TANG Yun ; YE Sheng ; LING Hua ; TAN Zhang-ping
China Tropical Medicine 2023;23(5):495-
Abstract: Objective To analyze the nucleic acid detection results of severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) by droplet digital PCR (ddPCR) and compare with the detection results of real-time fluorescence quantitative RT-PCR (qRT-PCR), so as to evaluate the advantages and disadvantages of detection, and to provide data support for optimizing the nucleic acid detection scheme of SARS-CoV-2. Methods According to the SARS-CoV-2 specific primer probe published by the China Center for Disease Control and Prevention, a ddPCR detection method for SARS-CoV-2 was designed. One sample was selected for sensitivity test after gradient dilution; six respiratory virus nucleic acid positive samples including seasonal H3N2 influenza virus and SARS-CoV-2 positive samples were selected for specificity test; five SARS-CoV-2 positive samples were selected for repeatability test; in addition, 30 positive and 20 negative SARS-CoV-2 samples were selected for multiple clinical samples testing, and the results were analyzed and compared with those of qRT-PCR. Results The ddPCR method can specifically detect SARS-CoV-2, and directly obtain the original copy number of the sample target gene to achieve accurate quantification; the sensitivity test of gradient dilution positive samples showed that qRT-PCR detected target genes in part of the 10-5 dilution of samples, and no target genes were detected in 10-6 dilution, while ddPCR detected all target genes in both 10-5 and 10-6 dilution of samples. The detection limit of ddPCR was two orders of magnitude higher than that of qRT-PCR, and the sensitivity was higher than that of qRT-PCR; in the comparison of the repeatability test results of the two methods, the coefficient of variation of ddPCR was 1.266%-11.814%, lower than 1.729%-26.174% of qRT PCR, and the repeatability was higher than qRT-PCR; among 50 clinical samples, 30 positive samples of confirmed cases of Coronavirus Disease 2019 (COVID-19) were detected by both methods, SARS-CoV-2 was successfully detected by both methods, and 20 negative samples of COVID-19 were detected by both methods, and the results were negative, with a coincidence rate of 100.00% (50/50). Conclusion The ddPCR method can accurately quantify SARS-CoV-2 with strong specificity, and its sensitivity and repeatability are higher than those of qRT-PCR, but it also has certain detection limitations and is more suitable for the detection of low load samples. In the actual detection, the two methods can be reasonably combined to improve the detection accuracy.
4.Identification of a new subtype of blaADC produced by Acinetobacter baumannii isolated in children.
Rui-zhen ZHAO ; Qian CHEN ; Yue-jie ZHENG ; Zu-huang MI
Chinese Journal of Epidemiology 2007;28(10):1009-1012
OBJECTIVETo investigate the genotype of blaADC which was a kind of AmpC produced by Acinetobacter baumannii (AB), isolated through the detection of 28 similar strains among children.
METHODS28 strains of AB were collected and isolated from the Pediatrics clinic during 2006, and were identified through bacteria and susceptibility test using Vitex-32 automicroscan GNI and GNS cards. The genotype of blaADC was confirmed by polymerase chain reaction (PCR) and them sequenced.
RESULTS3 of the 28 strains of AB showed multi-drugs resistance, with a positive rate of 10.71%. blaADC was discovered in 17 of the 28 strains and the positive rate was 60.71%. All the 28 strains of AB were resistant to Cefoxitin. blaADC positive strains were all sensitive to Ampicil/Sulbactam, and only one of them was resistant to Piperacillin/Tazobactan. There were no blaADC genes discovered in the strains that were resistant to Ampicil/Sulbactam or Piperacillin/Tazobactan. There were changes of amino acids on the site 4, 242, 342 and 376 in the sequence of blaADC of No.2 strain, comparing to gi /7258342/ emb /CAB77444. 1/ in GenBank.
CONCLUSIONAbove 60% of the AB isolated in children were carrying blaADC while a strain was collected from them at random. When they were undertaken nucleotide sequence analysis, significant difference was found from the others that landed in GenBank, which identified itself as new subtype.
Acinetobacter Infections ; microbiology ; Acinetobacter baumannii ; classification ; drug effects ; genetics ; isolation & purification ; Amino Acid Sequence ; Anti-Bacterial Agents ; pharmacology ; Bacterial Typing Techniques ; Child ; DNA, Bacterial ; genetics ; Drug Resistance, Multiple, Bacterial ; genetics ; Genotype ; Humans ; Microbial Sensitivity Tests ; Molecular Sequence Data ; Sequence Alignment ; Sequence Analysis, DNA ; beta-Lactamases ; genetics
5.Quantitative structure characteristics and fractal dimension of Chinese medicine granules measured by synchrotron radiation X-ray computed micro tomography.
Xiao-long LU ; Qin ZHENG ; Xian-zhen YIN ; Guang-qing XIAO ; Zu-hua LIAO ; Ming YANG ; Ji-wen ZHANG
Acta Pharmaceutica Sinica 2015;50(6):767-774
The shape and structure of granules are controlled by the granulation process, which is one of the main factors to determine the nature of the solid dosage forms. In this article, three kinds of granules of a traditional Chinese medicine for improving appetite and promoting digestion, namely, Jianwei Granules, were prepared using granulation technologies as pendular granulation, high speed stirring granulation, and fluidized bed granulation and the powder properties of them were investigated. Meanwhile, synchrotron radiation X-ray computed micro tomography (SR-µCT) was applied to quantitatively determine the irregular internal structures of the granules. The three-dimensional (3D) structure models were obtained by 3D reconstruction, which were more accurately to characterize the three-dimensional structures of the particles through the quantitative data. The models were also used to quantitatively compare the structural differences of granules prepared by different granulation processes with the same formula, so as to characterize how the production process plays a role in the pharmaceutical behaviors of the granules. To focus on the irregularity of the particle structure, the box counting method was used to calculate the fractal dimensions of the granules. The results showed that the fractal dimension is more sensitive to reflect the minor differences in the structure features than the conventional parameters, and capable to specifically distinct granules in structure. It is proved that the fractal dimension could quantitatively characterize the structural information of irregular granules. It is the first time suggested by our research that the fractal dimension difference (Df,c) between two fractal dimension parameters, namely, the volume matrix fractal dimension and the surface matrix fractal dimension, is a new index to characterize granules with irregular structures and evaluate the effects of production processes on the structures of granules as a new indicator for the granulating process control and optimization.
Drugs, Chinese Herbal
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analysis
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Fractals
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Medicine, Chinese Traditional
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Powders
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Quantitative Structure-Activity Relationship
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Synchrotrons
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Technology, Pharmaceutical
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Tomography, X-Ray Computed
6.Epidemiological analysis of plague in Qinghai province between 2000 and 2009
Ke-mei, WU ; Yong-hai, YANG ; Yuan-zhong, WANG ; Xue, WANG ; Zhi-zhen, QI ; Zu-yun, WANG
Chinese Journal of Endemiology 2011;30(4):437-440
Objective To analyze the endemic features of plague in Qinghai province between 2000 and 2009, discover the law of occurrence and progression, in order to provide a scientific basis for further prevention and treatment of the disease. Methods Descriptive epidemiology was employed to analyze the data from on the spot investigation, monitoring reports and papers published between 2000 and 2009. The indicators included the area, host and media distribution of animal plague and area, time, and population distribution of human plague.Results In Qinghai province between 2000 and 2009, 189 strains of Yersinia pestis were isolated from a variety of animals and insect vectors, including 77 from the marmot, accounting for 40.74%, 40 from Callopaylla dolabris,accounting for 21.16%. Positive serum antibodies against F1 plague were detected in 238 samples, including 90 samples from husbandry dogs, 63 from woodchucks. The areas with Yersinia pestis were consistent with the areas with positive serum antibodies against F1 plague, which distributed mainly along the Qinghai-Tibet railway Wulan county, Delhi and Golmud Multi-county;confirmed that there was natural foci of plague in Qinghai vole. Between 2000 and 2009, 13 events of human plague occurred, with 37 cases and 16 patients died, mortality was 43.24%.Cases were distributed in 11 townships of Tongde, Xinghai, Qilian, Wulan, Tianjun, Nangqian, Qumalai,Chengduo and Zhiduo counties. May to October was the disease season, with September the peak. Pneumonic plague disease type was the main mode of transmission of the plague and patients often contacted with airborne droplets through the air and peeling fresh Marmota. Conclusions Plague in Qinghai province is still grim,strengthening animal plague surveillance, and timely disposal of animal plague, improving the province's agricultural and pastoral areas, especially increase the disease prevention consciousness of the masses are future tasks. Work should be focused on strengthening the prevention and control of plague along Qinghai-Tibet railway,and prevent the occurrence and long-distance transmission of human plague.
7.Relation of pbp2B, ermB, ermA/B, mefA genes with resistance to penicillin and erythromycin among Streptococcus pneumoniae isolates from children.
Yun-fang DING ; Jian-hua ZHANG ; Zu-huang MI ; Yun-zhen TAO ; Ling QIN
Chinese Journal of Pediatrics 2005;43(5):364-367
OBJECTIVETo investigate the relation of pbp2B, ermB, ermA/B and mefA genes to penicillin and erythromycin resistance among isolated Streptococcus pneumoniae (Sp) in children.
METHODSTwenty-six strains of Sp were collected from September 2002 to April 2003 at the Children Hospital of Suzhou University. (1) Twenty-six pneumococcal isolates were obtained from respiratory tract secretions of children with respiratory diseases. (2) Susceptibility of the isolates to penicillin, cefuroxime, ceftriaxone, cefotaxime and erythromycin was determined by E-test. (3) The genes pbp2B, ermB, ermA/B and mefA of the isolates were detected with PCR. (4) The PCR product of pbp2B gene was sequenced. (5) DNA sequences of pbp2B of pneumococcal isolates were compared with those of SpR6 [penicillin sensitive (www.ncbi.nlm.gov/nucleotide, NC-003098)].
RESULTSAmong the 26 isolates studied, pbp2B gene mutation was found in 15(58%) isolates, all were point mutation of A, B, C and D genotypes which were seen in 11(73%), 2(13%), 1(7%) and 1(7%), respectively. The numbers of isolates susceptible to penicillin, cefuroxime, ceftriaxone and cefotaxime were 9(82%), 10(91%), 11(100%) and 11(100%), of 11 non-mutation isolates;numbers of isolates resistant to penicillin, cefuroxime, ceftriaxone, and cefotaxime were 13(87%), 11(73%), 1(7%) and 1(7%) out of 15 isolates with mutation.ErmB, ermA/B, mefA and erm/mef genes were positive in 9(35%), 16(62%), 7(27%) and 21(81%)isolates. MIC of erythromycin was 2 to > 256 mg/L among pneumococcal isolates with erm/mef genes.
CONCLUSIONAmong antibiotic resistant pneumococcal isolates in the area, the main basis of penicillin resistance was the mutation of pbp2B genes. Genotype A mutation had the highest rate among the isolates with mutation and manifested as resistance to penicillin and cefuroxime. Expression of either all or any of the ermA, ermB and mef genes led to erythromycin resistance. Antibiotics resistant Sp strains in this area are forming a challenge to efficacy of penicillin and erythromycin.
Aminoacyltransferases ; genetics ; Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; Child ; Drug Resistance, Bacterial ; Erythromycin ; pharmacology ; Humans ; Membrane Proteins ; genetics ; Methyltransferases ; genetics ; Penicillin Resistance ; Penicillin-Binding Proteins ; genetics ; Streptococcus pneumoniae ; drug effects ; genetics
8.Study on the molecular epidemiology of beta-lactamase TEM gene in isolated Streptococcus pneumoniae.
Yun-fang DING ; Jian-hua ZHANG ; Zu-huang MI ; Ling QIN ; Yun-zhen TAO ; Xiao QI
Chinese Journal of Epidemiology 2004;25(11):970-972
OBJECTIVETo investigate the beta-lactamase TEM gene of isolated Streptococcus pneumoniae (Sp) in Suzhou area.
METHODSTwenty-three strains of Sp were collected from respiratory tract secretions of children with respiratory diseases in Nov 2002 to Apr 2003 at Children's Hospital of Suzhou University (reference strain ATCC49619) to build TEM polymerase chain reaction (PCR) system (reference strain E. coli. 9-j53R1 with TEM gene) TEM gene of 23 strains was detected to comparo the sequences with published TEM gene sequences in GenBank for analyzing TEM gene model.
RESULTSTwenty-one strains had TEM gene with a positive rate of 91.3% (21/23). TEM-129 gene were confirmed from No.17 (SR017, penicillin resistance) TEM sequence. New discovered TEM-129 sequence had a modification (ATG[M]-->ATA[I]) at No.182 code and published (GenBank: www.ncbi.nlm.nih.gov/nucleotide, AY452662). TEM-1 genes were confirmed from other TEM sequences. New discovered TEM-1 gene of isolated Sp had been published (GenBank: www.ncbi.nlm.nih.gov/nucleotide, AY392531) too.
CONCLUSIONIsolated Sp had TEM gene (TEM-129, EM-1 genotype) with a positive rate of 91.3%. The result enriched the understanding of isolated Sp with penicillin resistance.
Base Sequence ; China ; epidemiology ; Drug Resistance, Bacterial ; genetics ; Female ; Genes, Bacterial ; genetics ; Humans ; Male ; Molecular Epidemiology ; Molecular Sequence Data ; Pneumonia, Bacterial ; epidemiology ; genetics ; microbiology ; Point Mutation ; Streptococcus pneumoniae ; enzymology ; genetics ; beta-Lactam Resistance ; beta-Lactamases ; genetics
9.Study on the molecule epidemiological between resistances of 7 genes interrelated 4 antibiotic to isolated Streptococcus pneumoniae in children.
Yun-fang DING ; Zu-huang MI ; Jian-hua ZHANG ; Yun-zhen TAO ; Ling QIN
Chinese Journal of Epidemiology 2005;26(6):435-439
OBJECTIVETo investigate the molecule epidemic for 7 genes interrelated penicillin, erythromycin, tetracycline, vancomycin resistance of isolated Streptococcus pneumoniae (SP) in children at Suzhou area.
METHODS(1) Thirty-one pneumococcal isolates were collected from respiratory tract secretions of children with respiratory diseases from Nov 2002 to Apr 2003 at the Children's Hospital of Suzhou University (reference strain ATCC49619). (2) Penicillin susceptibility was determined by E-test, while erythromycin, tetracycline, vancomycin were determined by K-B disk. (3) The detecting of pbp2B, ermA/B, mefA, tetM, vanA, vanB genes by PCR, Sequencing pbp2B genes, Contrasting pbp2B DNA sequences among pneumococcal isolates and SP R6 [penicillin sensitive (www.ncbi.nlm.gov/nucleotide, NC-003098)].
RESULTSOf thirty-one isolates studied, the results were shown as follows; (1) Penicillin sensibility 38.7% (n = 12), penicillin resistance 61.3% (n = 19), pbp2B mutation 64.5% (n = 20); (2) Erythromycin sensibility 9.7% (n = 3), erythromycin resistance 90.3% (n = 28), ermA/B 71% (n = 22), mefA 32.1% (n = 10), ermA/B + mefA 87.1% (n = 27); (3) Tetracycline sensibility 9.7% (n = 3), tetracycline resistance 90.3% (n = 28), tetM 90.3% (n = 28); (4) Vancomycin sensibility 100% (n = 31), vanA, vanB all 0%.
CONCLUSIONAmong pneumococcal isolates at our area, penicillin, erythromycin, tetracycline resistance were high, vancomycin was sensitive. Detecting 7 genes interrelated penicillin, erythromycin, tetracycline, vancomycin resistance expressed genotypies for antibiotic resistances in pneumococcal isolates.
Anti-Bacterial Agents ; pharmacology ; Child ; China ; epidemiology ; DNA, Bacterial ; genetics ; Drug Resistance, Multiple, Bacterial ; genetics ; Erythromycin ; pharmacology ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Molecular Epidemiology ; Penicillin Resistance ; genetics ; Pneumococcal Infections ; epidemiology ; microbiology ; Streptococcus pneumoniae ; drug effects ; genetics ; isolation & purification ; Tetracycline Resistance ; genetics ; Vancomycin ; pharmacology
10.Study on combined gene therapy for malignant gliomas transfected with antisense hTERT/PTEN in vitro and in vivo.
Yong-ping YOU ; Zhen FU ; Peng ZHAO ; Cun-zu WANG ; Ning LIU ; Ai-lin LU
Chinese Journal of Medical Genetics 2006;23(6):605-609
OBJECTIVETo study inhibitory efficacy of combined gene therapy for malignant gliomas transfected with antisense human telomerase reverse transcriptase (hTERT)/PTEN in vitro and in vivo.
METHODSTo construct two adenovirus recons which contained antisense hTERT and wild-type PTEN respectively with high performance homologous recombination system in bacteria. The two adenovirus recons were transfected into U251 human malignant glioma cells combinedly or respectively in vitro and in vivo. U251 cell proliferation in vitro was determined by MTT assay and flow cytometry, tumor growth in vivo was measured by the volume of glioma in nude mice. Telomerase activity was detected by telomeric repeat amplification protocol (TRAP) assay. Expression of hTERT and PTEN protein was detected by Western blotting methods.
RESULTSAfter transfection in vitro, the growth of U251 cells was inhibited significantly. The inhibitory effect was time-dependent. The strongest inhibition was observed in combined transfection group, at the 6th day, the survival rate was 37.6%, telomerase activity (only 28.8TPG) was inhibited significantly, hTERT protein expression was inhibited significantly too, which was 0.2106, but PTEN protein expression was increased significantly, which was 0.9630. In vivo, the growth of tumors was also effectively inhibited.
CONCLUSIONGrowth of malignant glioma cells is effectively inhibited after transfection with combined antisense hTERT and PTEN in vitro and in vivo.
Adenoviridae ; genetics ; Animals ; Apoptosis ; Blotting, Western ; Brain Neoplasms ; pathology ; therapy ; Cell Line, Tumor ; Cell Proliferation ; DNA, Antisense ; genetics ; metabolism ; Flow Cytometry ; Genetic Therapy ; methods ; Glioma ; pathology ; therapy ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Mice ; Mice, Nude ; Microscopy, Fluorescence ; PTEN Phosphohydrolase ; genetics ; Recombinant Fusion Proteins ; genetics ; metabolism ; Telomerase ; genetics ; metabolism ; Transfection ; Tumor Burden ; Xenograft Model Antitumor Assays